The response of plasma-facing materials to off-normal high heat loads expected in Next European Torus/International Thermonuclear Experimental Reactor (NET/ITER) disruptions has been studied by both experimental and numerical simulations. Experiments have been performed on a number of pyrolytic graphites and carbon-fiber composites. The measured erosion is compared with numerical predictions by a transient heat load code. The effect of variations in thermophysical material parameters on thermal erosion behavior is discussed. Cracking is observed on the surface of pyrolytic graphites, even below the erosion threshold.